REGIONAL METALLOGENY OF THE “WUDANG MASSIF” IN HUBEI PROVINCE

1.According to the gravity,seismic and stratigraphic data, the section of the earth’s crust in the area has been established and the mineralization boundaries have been defined. （1） Lower crust.The crust in the area is 34—39 km thick.A group of seismic focuses are concentrated at depths of 37—38 km. Mineralization boundary I lies between the base of the crust and the asthenosphere of the upper mantle. （2） Upper crust.A group of seismic focuses are concentrated at a depth of 9 km,the depth being consistent with the thickness of the Proterozoic strata in the area.The rocks include mainly acid extrusives and less commonly basic extrusives,intercalated with large amounts of sediments.The late stage witnessed first an ice age,then basic volcanic eruption and finally accumulation of magnesian carbonte rocks of the marginal sea.Mineralization boudary Ⅱ of the area lies just here.There occur silver,gold,copper,lead,zinc,phosphorite and blue asbestos. A group of seismic focuses are concentrated at depths of 4—5 km.The depths represent the boundary between the Paleozoic and Proterozoic.There occurred basic,intemediatebasic and alkaline volcanic eruptions and accumulations of argillaceous,arenaceous and carbonate rocks.Here lies mineralization boundary ;Ⅲ.There are Vanadium,uranium,thorium,mercury,antimony, niobium-REE,iron,platinum,barite,pyrite,phosphorite,turquoise and stone coal. One group of seismic focuses are concentrated at a depth of 2 km, this depth representing the thickness of the Mesozoic and Cenozoic continental sediments.Here lies mineralization boundary Ⅳ.There occur copper, placer gold,gypsum,celestine,germanium,kaoline and alum stone. 2.There is a definite range of action in time and space for mineralization.For each mineralization boundary,several polymineral or monomineral range zones,synchronous composite range zones, allochtbonous polymineral range zones,diachronous range zones,layer-spanning range zones and deepsource range zones may be distinguished. 3.Isotope geology is closely related to the mineralization range zones. Various isotope data such as sulfur,hydrogen,oxygen and carbon isotope data as well as isotopic age class data may likewise be used as a basis for distinguishing mineralization boundaries and range zones. 4.There is no fixed form for a mineralization boundary.It may be distorted or fractured with structural movements and ore-bearing solutions may sneak their way into it in order to look for a new repository.On this basis,the mantle in the area is studied,thus leading to the conclusion that the N-S-trending Danhan and Zhuxi fractures occurring in the area are the main mineralization-holding structures.